Faculty of Geosciences and Environmental Engineering, Southwest Jiaotong University, Chengdu, 610059, China.
School of Food and Biological Engineering, Xihua University, Chengdu, 610039, China.
Sci Rep. 2023 Feb 22;13(1):3121. doi: 10.1038/s41598-023-29983-1.
The bacterial phoD gene encoding alkaline phosphatase (ALP) plays an important role in the release of soluble reactive phosphorus (SRP) from organic phosphorus in ecosystems. However, phoD gene diversity and abundance in ecosystems is poorly understood. In the present study, we sampled the surface sediments and the overlying water of Sancha Lake at 9 different sampling sites, a typical eutrophic sub-deep freshwater lake in China, in April 15 (spring) and November 3 (autumn), 2017. High-throughput sequencing and qPCR were performed to analyze the diversity and abundance of the bacterial phoD gene in the sediments. We further discussed the relationships between the diversity and abundance of the phoD gene and environmental factors and ALP activity. A total of 881,717 valid sequences were obtained from 18 samples and were classified into 41 genera, 31 families, 23 orders, 12 classes, and 9 phyla and grouped into 477 OTUs. The dominant phyla were Proteobacteria and Actinobacteria. The phylogenetic tree based on the sequences of the phoD gene was plotted and composed of three branches. The genetic sequences were aligned predominantly with genera Pseudomonas, Streptomyces, Cupriavidus, and Paludisphaer. The phoD-harboring bacterial community structure showed a significant difference in spring and autumn, but no apparent spatial heterogeneity. The phoD gene abundances at different sampling points were significantly higher in autumn than in spring. In autumn and spring, the phoD gene abundance was significantly higher in the tail of lake and where cage culture used to be intensive. pH value, dissolved oxygen (DO), total organic carbon (TOC), ALP, and phosphorus were important environmental factors affecting the diversity of the phoD gene and the phoD-harboring bacterial community structure. Changes in phoD-harboring bacterial community structure, phoD gene abundance, and ALP activity were negatively correlated with SRP in overlying water. Our study indicated phoD-harboring bacteria in the sediments of Sancha Lake with the characteristics of high diversity and significant spatial and temporal heterogeneity in abundance and community structure, which played a important role in the release of SRP.
该研究于 2017 年 4 月 15 日（春季）和 11 月 3 日（秋季）在 9 个不同采样点采集了中国典型富营养化亚深水湖泊三汊湖表层沉积物和上覆水样品，利用高通量测序和 qPCR 分析了沉积物中细菌 phoD 基因的多样性和丰度，并进一步探讨了 phoD 基因多样性和丰度与环境因子和碱性磷酸酶（ALP）活性之间的关系。共获得 18 个样品的 881717 条有效序列，可分为 41 属、31 科、23 目、12 纲和 9 门，聚类为 477 个 OTUs。优势门为变形菌门和放线菌门。基于 phoD 基因序列构建的系统发育树分为 3 个分支，序列主要与假单胞菌属、链霉菌属、贪铜菌属和浮霉菌属的亲缘关系较近。 phoD 基因丰度在春秋两季存在显著差异，但无明显的空间异质性。秋季各采样点 phoD 基因丰度显著高于春季。秋季和春季，湖尾和网箱养殖密集区的 phoD 基因丰度显著较高。pH 值、溶解氧（DO）、总有机碳（TOC）、ALP 和磷是影响 phoD 基因多样性和 phoD 基因丰度和携带细菌群落结构的重要环境因素。上覆水中 SRP 与 phoD 基因携带细菌群落结构、 phoD 基因丰度和 ALP 活性的变化呈显著负相关。本研究表明，三汊湖沉积物中 phoD 基因携带细菌具有丰富的多样性，丰度和群落结构具有显著的时空异质性，在释放 SRP 方面发挥了重要作用。
